The present invention relates to igniters, and more particularly to igniters for use in gasoline engines, diesel engines and gas turbine engines, and that may be more rapidly and easily replaced in conventional igniters.
Ordinary spark plugs have an external thread on a metal outer housing or shell with a hexagonal head integrally formed with the metal outer shell and adapted for mating with a removal tool such as a socket or a box end wrench. The outer shell is seated in a threaded bore of a cylinder head and may have a deformable gasket seal located between the hexagonal head and the cylinder head, thereby isolating the cylinder chamber. Complete sealing and correct positioning of a spark plug in the combustion chamber requires applying a precise torque to the hexagonal head of the spark plug. Excessive torque or incorrect positioning may strip the threads in the cylinder head, requiring expensive repairs. Space for tools is limited in many engine compartments and access is often awkward. All the problems associated with spark plug replacement are magnified in auto racing competition where engine heat is much greater than in conventional engines and where time constraints are added. Similar problems to those discussed above are associated with the replacement of glow plugs in diesel engine applications and igniters in gas turbine engine applications.
U.S. Pat. No. 5,186,132, issued to Runge teaches a plug-in spark plug that requires a special bore in the cylinder head with a retaining groove for engaging a locking clip. The plug-in spark plug as disclosed in the Runge patent requires some sort of tool fitting in a groove to forcefully pull the plug out and a tool for engaging the clip to the reduce its diameter to disengage it from the retaining area. It would be desirable to have a system that would operate with conventional bored and threaded engine components, since it would be impractical for engine manufacturers to provide specially designed engine components.
U.S. Pat. No. 3,747,583, issued to Georges and Spangler teaches a quick insertion spark plug arrangement in which an outer sleeve screws into the threaded bore in a cylinder head. The sleeve has an inner profile that cooperates with an outer profile of a plug. When in a first rotary position, the plug may be moved axially into and out of the sleeve. When the inserted plug is a second rotary position, the outer profiles cooperate to lock the position of the plug against axial movement, thus preventing the spark plug from being axially removed from within the sleeve. The spark plug as disclosed by Georges and Spangler does not prevent rotational movement of the plug from within the sleeve towards an unlocked position.
Quick disconnect couplings for joining conduits for high pressure fluids are exemplified in U.S. Pat. No. 3,162,470, issued to Davidson, and SWAGELOK (registered trademark) fluid flow quick-connect coupling QF series made by the SWAGELOK Company of Hudson, Ohio. Each of these couplings as disclosed include a hand-operated sliding lock sleeve that requires no tool for engagement and disengagement. This style of connection has not been applied to spark plugs, glow plugs, or gas turbine igniters.
One aspect of the present invention is to provide a two-piece igniter that includes an outer housing that includes a cylindrical member having an outer wall and an inner wall, the inner wall defining a passage through the outer housing, and having a first profile having at least one undercut section and defining a first diameter, and a second profile defining a second diameter. The igniter further includes a plug member adapted to fit within the passage of the outer housing and that includes an axial electrode and an electrically insulating insulator element encircling the axial electrode. The axial electrode includes a first end for connection to an electric source and a second end for engagement within a combustion area. The plug member is provided a first profile and a second profile, the second profile adapted to be received within the undercut section of the first profile of the outer housing. The plug member may be releasably coupled within the outer housing by inserting the plug member within the passage of the outer housing and turning the plug member with respect to the outer housing, thereby locating the second profile of the plug member within the undercut section of the first profile of the outer housing. The biasing member biases the second profile of the plug member into engagement with the undercut section of the first profile of the outer housing.
Another aspect of the present invention is to provide a method of coupling a two-piece igniter that includes providing an outer housing including a cylindrical member having an outer wall and an inner wall that finds a passage through the outer housing, wherein the inner wall has a first profile defining a first diameter and a second profile defining a second diameter, and the first profile has at least one inwardly extending step. The method further includes providing a plug member adapted to fit within the passage of the outer housing, wherein the plug member includes an axial electrode and an electrically insulating insulator element encircling the axial electrode. The axial electrode has a first end for connection to an electric source and a second end for engagement within a combustion area, and the plug member has a first profile defining a first diameter and a second profile defining a second diameter. The method also includes providing a longitudinally extending biasing member positioned about the plug member and adapted to two outwardly bias the plug member from within the outer housing, inserting the plug member within the passage of the other housing, and exerting an inwardly directed force on the plug member, thereby depressing the biasing member. The method still further includes turning the plug member with respect to the outer housing until the second profile of the plug member is rotated beyond the at least one step of the outer housing, and releasing the inwardly directed force on the plug, such that the at least one step of the outer housing restricts the plug member from being rotated with respect to the outer housing.
Another aspect of the present invention is to provide a two-piece igniter that includes an outer housing that includes a cylindrical member having an outer wall and an inner wall, the inner wall defining a passage through the outer housing. The outer housing further includes at least one biasing member and at least one engagement member inwardly biased by the biasing member such that the engagement member moveably extends within the passage. The igniter further includes a plug member adapted to fit within the passage of the outer housing and that includes an axial electrode and an electrically insulating insulator element encircling the axial electrode. The axial electrode has a first end for connection to an electric source and a second end for engagement within a combustion area. The insulator element includes a circumferentially extending annular groove adapted to receive the engagement member of the outer housing therein. The plug member may be releasably coupled within the outer housing by inserting the plug member within the base of the outer housing to an engagement position wherein the engagement member of the outer housing engages the annular groove of the insulator element of the plug member. The plug member may be uncoupled from within the outer housing by inserting the plug member beyond the engagement position and then removing the plug member from within the outer housing.
Yet another aspect of the present invention is to provide a two-piece igniter that includes an outer housing including a cylindrical member having an outer wall and an inner wall that defines a passage through the outer housing and that has at least one inwardly extending first projection. The igniter also includes a plug member adapted to fit within the passage of the outer housing and that includes an axial electrode and an electrically insulating insulator element encircling the axial electrode, the axial electrode having a first end for connection to an electric source and a second end for engagement within the combustion area. The plug member has at least one outwardly extending second projection adapted to engage the first protection of the outer housing. The igniter further includes a longitudinally extending biasing member positioned about the plug member and exerting both a linear and rotation force on the plug member as the biasing member is compressed. The plug member may be releasedly coupled within the outer housing by inserting the plug member within the passage of the outer housing and placing an inwardly directed first force on the plug member until the first and second projections are engaged and then releasing the first force. The plug member may be uncoupled from within the outer housing by placing an inwardly directed second force on the plug member until the first and second projections are not engaged and then releasing the second force and removing the plug member from within the outer housing.
Yet another aspect of the present invention is to provide a method that includes providing an outer housing including a cylindrical member having an outer wall and an inner wall that defines a passage through the outer housing and that includes at least one inwardly extending first projection, and providing a plug member adapted to fit within the passage of the outer housing. The plug member includes an axial electrode and an electrically insulating insulator element encircling the axial electrode. The axial electrode has a first end for connection to an electric source and a second end for engagement within a combustion area. The plug member has at least one outwardly extending second projection adapted to engage the first projection of the outer housing. The method also includes providing a biasing member positioned about the plug member and that exerts both a linear and a rotational force around the plug member as the biasing member is compressed, inserting the plug member within the outer housing, and applying an inwardly directed first force to the plug member until the spring aligns the second projection with the first projection, thereby engaging the second projection with the first projection and releasably locking the plug member within the outer housing, and releasing the inwardly directed first force.
Still yet another aspect of the present invention is to provide a method that includes providing an outer housing including a cylindrical member having an outer wall and an inner wall, the inner wall defining a passage through the outer housing, and providing a plug member adapted to fit within the passage of the outer housing including an axial electrode and an electrically insulating insulator element encircling the axial electrode, the axial electrode having a first end for connection to an electric source and a second end for engagement within a combustion area. The method still further includes providing a first biasing member positioned within the plug member, inserting the plug member within the outer housing, applying an axially directed force to the plug member, thereby compressing the biasing member, and releasing the axially directed force, thereby releasably locking the plug member within the outer housing.
These and other features, advantages, and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification and appended drawings.